c# - Public fields/properties of a class derived from BindingList<T> wont serialize

Question

I'm trying to serialize a class that derives from BindingList(Floor), where Floor is a simple class that only contains a property Floor.Height

Here's a simplified version of my class

[Serializable]
[XmlRoot(ElementName = "CustomBindingList")]
public class CustomBindingList:BindingList<Floor>
{
    [XmlAttribute("publicField")]
    public string publicField;
    private string privateField;

    [XmlAttribute("PublicProperty")]
    public string PublicProperty
    {
        get { return privateField; }
        set { privateField = value; }
    }
}

I'll serialize an instance of CustomBindingList using the following code.

XmlSerializer ser = new XmlSerializer(typeof(CustomBindingList));
StringWriter sw = new StringWriter();

CustomBindingList cLIst = new CustomBindingList();

Floor fl;

fl = new Floor();
fl.Height = 10;
cLIst.Add(fl);

fl = new Floor();
fl.Height = 10;    
cLIst.Add(fl);

fl = new Floor();
fl.Height = 10;
cLIst.Add(fl);

ser.Serialize(sw, cLIst);

string testString = sw.ToString();

Yet testString above ends getting set to the following XML:

<CustomBindingList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <Floor Height="10" />
    <Floor Height="10" />
    <Floor Height="10" />
</CustomBindingList>"

How do I get "publicField" or "publicProperty to serialize as well?

Answer 1

The short answer here is that .NET generally expects something to be a collection xor to have properties. This manifests in a couple of places:

• xml serialization; properties of collections aren't serialized
• data-binding; you can't data-bind to properties on collections, as it implicitly takes you to the first item instead

In the case of xml serialization, it makes sense if you consider that it might just be a SomeType[] at the client... where would the extra data go?

The common solution is to encapsulate a collection - i.e. rather than

public class MyType : List<MyItemType> // or BindingList<...>
{
    public string Name {get;set;}
}

public class MyType
{
    public string Name {get;set;}
    public List<MyItemType> Items {get;set;} // or BindingList<...>
}

Normally I wouldn't have a set on a collection property, but XmlSerializer demands it...